Bisphenol A is prepared from a reaction of acetone and excessive phenol in the presence of an acidic catalyst. In order to obtain high-purity bisphenol A from this reaction product, low boiling point materials including water is removed, bisphenol A and/or solid adduct crystals of bisphenol A and phenol are precipitated by crystallization, a slurry including the solid adduct is separated into solids and liquids, and phenol is removed from the recovered solid adduct, so that bisphenol A is obtained.
A continuous crystallization process has been industrially used to efficiently purify a large amount of a reactant. In the continuous crystallization process, a slurry including the solid adduct obtained within a crystallizer is separated into solids and liquids, and a solid adduct is recovered and a liquid phase remains. The liquid phase includes phenol in an amount of about 70 wt %, bisphenol A in an amount of about 15 wt %, and other by-products. Thus, in order to reuse phenol included in the liquid phase, a reaction mother liquid from which some by-products are removed is cyclically supplied to a reactor that requires excessive phenol. In this process, it is required to increase the efficiency of the reactor in the above-described reaction.